Rheostat



J. H. MILLER Sept. 2 1924.

RHEOSTAT Original Filed April 28, 22

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Patented Sept. 2, 19 24.

UNITED STATES JOHN H. MILLER, 01' OAK PARK, ILLINOIS.

RHEOSTAT.

Application filed April 28, 1922, Serial 1T0. 557,185. Renewed July 21, 1924.

To all whom it may concern:

Be it known that I, JOHN H. MILLER, a citizen of the United States, and resident of Oak Park, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Rheostats, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

This invention relates to variable resistances or rheostats.

The object of the invention is to provide a rheostat which consists of. the minimum number of parts, which will be simple and cheap to manufacture, which will provide a great number of adjustments, and in which the danger of disarrangement of the parts is reduced to the minimum.

One of the features of the invention is the arrangement of the resistance conductors so that their own tension maintains contact with the movable bridging member throughout the range of adjustment.

Other features of the invention reside in the particular means of mounting the resistance elements and the bridging device, as will hereinafter appear from the detailed description.

In the drawings,

Figure 1 is a side elevation of the rheostat of the invention;

Figure 2 is a plan view thereof;

Figure 3 is a sectional view on the line 33 of Figure 1 looking in the direction of the arrows, and

1 Figure 4 isa section on the line 4--4 of Figure 1 looking in the direction of the arrows.

Referring now to the drawings, in which like reference characters indicate like parts in the several views, 10 indicates a panel or mounting plate to which the rheostat may be attached. The various elements of the rheostat are carried by the circular block 11 of insulating material. The block 11 may be secured to the mounting plate 10 b means of the screws 12, the heads 13 of W ich are positioned Within the annular depression 14 in the side of the block 11.

Extendin through an opening 15 in the mounting p ate 10, and through the aligned opening 16 which passes concentrically through the block 11, is the shaft 17. Mounted within a recess 18 in; the block 11 is a metallic disc 19. The shaft 17 is provided with a shoulder 20 which engages one surface of the disc 19. Secured to one end of the shaft 17 is the knob or hand piece 21 of insulating material. Secured to the opposite end of the shaft 17, in any desired manner, as by means of solder, is a radially extending arm 22.

urrounding the shaft 17 and positioned between the arm 22 and the face of the block 11 is a spring washer 23 which acts to maintain the parts in firm engagement, and also operates to cause friction so as to maintain the arm 22 in any adusted position to which it may be moved. Secured to the outer end of the arm 22 is a strip of conducting material 24 having a portion 25 extending laterally across the edge ofthe block 11 and then rebent as at 26 to lie within the notch or groove 27 formed about the inner corner of the block 11.

Extending inwardly from the o posite sides of the upper portion of the b ock 11 are the slots or notches 28 and 29, respectively, having the enlarged portions 30 and 31 in which the knots or enlargements 32 and 33, at the ends of the resistance conductors 34 and 35, are received.

Extending substantially around the circumference of the block 11 is a pair of substantially parallel grooves 36 and 37 in which the conductors 34 and 35, res ectively, are adapted to normally lie. Mou ded into the block 11 are the laterally extending base portions 38 and 39 of the terminal members 40 and 41, which are provided with the cut out lug portions 42 and 43. The resistance element 34 is passed about the block 11 in the groove 36, thence over the In 44, downwar ly through the slot or note 45 in the mounting block flange, and is wound about and secured, in any desired manner, as by solder, to the lug 42 of the terminal member '40. In like manner, the resistance element 35 passes about the block 11 in the groove 37, over the lug 46, downwardl through the slot 47, and is secured to the lug 43 of the terminal member 41. The resistance elements 34 and 35, adjacent to the slots 28 and 29, pass over the hump 49 before entering the grooves 36 and 37, respectively.

As previously noted, the bridging member 25, at the end of the arm 22, is arranged to pass immediately adjacent to the circumference of the block 31 and under the resistance elements 34 and 35. Thus, whenever the bridging member 25 occupies a position anywhere about the circumference of the block 11, other than immediately adjacent to the hump 49, the tension of the resistance ele ments 34 and 35 brings them firmly into enagement with the outer surface of the 'firidging member, the resistance elements be- .ing raised up out' of the grooves 36 and 37 as the member 25 passes thereunder.

' Thus, it will be seen that by applicants arrangement an almost infinite number of adjustments of the resistance device may be obtained, and by moving the contact maker or bridging element immediately adjacent to-the hump 49, engagement with the resistance elements is entirely broken. As the resistance elements are maintained in engagement with the contact maker by their own tension and have a rubbing engagement therewith, the danger of the device being rendered inoperative or inaccurate by reason'of a dirty or open contact is reduced to a minimum.

While in the drawings and in the above description, certain details only have been disclosed, it is to be understood that applicant contemplates modifications in many of the details of his invention, and the invention, therefore, should be limited merely by the scope of the appended claims.

Having now described my invention, what I claim asnew and desire to secure by Letters Patent of the United States is:

1. In a rheostat, a resistance element, a support therefor having a curved surface about which said element lies, a movable contact member positioned between said surface and said element, and means for adj usting said contact member along said curved surface, said resistance element being maintained by its own tension in engagement with said contact member during the movement thereof.

2. In a rheostat, a support having a curved surface, resistance elements arranged substantially parallel on said surface, a movable contact member positioned between said elements and said surface, and means for adjusting said contact member along said surface, said elements being maintained by their own tension in engagement with said contact member during the movement thereof. 3. In a rheostat, a resistance element, a support therefor having a curved surface about which said element lies, a movable contact member positioned between said surface and saidresistance element, means for adjusting. said contact member along said curved surface, said resistance element being maintained by its own tension in engagement with said contact member during the movement thereof, and a hump onsaid surface ov'erwhich said element passes so arranged that when said contact is adjacent to said hump, said element is out of engagement therewith.

4. In a rheostat, a support having a curved surface, a groove in said surface, a resistance element positioned about said surface within said groove, a movable contact member positioned between said surface and said element, and means for adjusting said contact member along said curved surface, said resistance element being maintained by its own tension in engagement with said contact member during the movement thereof.

5. In a rheostat, a support having a curved surface, a pair of substantially parallel grooves in said surface, a pair of resistance elements positioned about said surface within'said grooves respectively, a movable contact member positioned between said surface and said elements, and means for adjusting said contact member along said curved surface, said resistance elements-being maintained by their own tension in engagement with said contact member during the movement thereof.

6. In a rheostat, a support having curved surface, a pair of resistance elements, a pair of substantially parallel grooves in said surface in which said elements are positioned respectively, a movable contact member positioned between said surface and said elements, means for adjusting said contact member along said curved surface, said resistance elements being maintained by their own tension in engagement with said contact member during the movement thereof, and a hump on said surface adjacent to one end of said elements over which said elements pass, said 'hump being arranged to position said elements from said surface.

7. In a rheostat, a generally circular block, a resistance element passing about a portion of the circumference of saidblock, a movable contact maker positioned between said block. and said element, and means for adjusting said. contact maker, around said block, said resistance element being maintained by its own tension in engagement with said contact maker during the movement thereof.

8. In a rheostat, a block, a pair of substantially parallel resistance elements positioned about a portion of the circumference of said block, a movable contact maker positioned between said block and said resistance, and means foradjusting said-contact maker about the circumference of said block, said resistance elements being maintained by their own tension in engagement with said contact maker during the movement thereof.

generally circular 9. In a rheostat a generally circular portion of the circumference of said block in which said elements are positioned respectively, a movable contact maker positioned between the circumference of said block and said elements, and means for adjusting said contact maker around said block, said resistance elements being maintained by their own tension in engagement with said contact maker during the movement thereof.

10. In a rheostat, a generally circular block, a pair of resistance elements, a pair of substantially parallel grooves about the circumference of said blockin which said elements are positioned a contact maker positioned between the circumference of said block and said elements, means for adjusting said contact maker along said circumference, said elements being maintained by their own tension in engagement with said contact maker during the movement thereof, and a hump on said circumference over which said elements pass so arranged that when said contact is adj acent to said hump, said elements are out of engagement therewith.

11. In a rheostat, a support having an arcuate surface, a resistance element arranged to normally snugly engage said sur face, a shaft mounted concentrically of said surface, an arm carried by said shaft, a contact maker on said arm arranged between said surface and said element, and means for rotating said shaft for adjustin said contact maker about said surface, sai resistance element being maintained by its own tension in engagement with said contact maker during the movement thereof.

12. In a rheostat, a substantially cylindrical block, a pair of substantially parallel grooves extending about the circumference of said block, a pair of resistance elements positioned within said grooves respectively, a shaft mounted concentrically of said block, an arm carried by said shaft, a contact maker on said arm arranged to be positioned between the circumference of said block and said resistance elements, means for rotating said shaft to adjust said contact maker about said block, said resistance elements being maintained in engagement with said contact maker b their own tension during the movement 0 said contact maker, and a I hump on the circumference of said block over which said resistance elements pass adjacent'to one end thereof such that said contact maker is out of engagement with said elements when positioned adjacent to said hump.

13L In a rheostat, a substantially circular block of insulating material, a pair of terminal members having base portions secured within said block, a pair of resistance elements extending about the circumference of said block and secured at one end to said terminal members respectively, a rotatable shaft extending concentrically through said block, an arm carried by said shaft. a contact maker on said arm arranged between the circumference of said block and said elements. and means for rotating said shaft whereby said contact maker may be adjusted along said resistance clen'ients, said resistance elements being maintained by their own tension in engagement with said contact maker during the movement thereof.

14. In a rheostat, a substantially circular block of insulating material, terminal members having base portions secured within said block, a pair of substantially parallel grooves about the circumference of said block, a pair of resistance elements positioned Within said grooves and having their ends secured to said terminal members respectively, a rotatable shaft extending concentrically through said block, an arm on said shaft, and a contact maker on said arm arranged to be positioned between the circumference of said block and said resistance elements.

15. In a 'rheostat, a substantially circular block of insulating material, terminal members having base portions secured within said block, a pair of substantially parallel grooves about the circumference of said block, a pair of resistance elements positioned within said grooves and having their ends secured to said terminal members respectively, a rotatable shaft extending concentrically through said block, an arm on said shaft, a contact maker on said arm arranged to be positioned between the circumference of said block and said resistance elements, and a hump on the circumference of said block adjacent to said terminal members over which said resistance elements pass.

16. In a rheostat, a generally circular block, a pair of resistance elements, a pair of notches in the circumference of said block in which the ends of said elements are secured respectively, a pair of terminal members, each having a base portion secured within said block, said resistance elements being passed about the circumference of said block and secured to said terminal members, a shaft extending concentrically through said block, a contact maker carried by said shaft and arranged between the circumference of said block and said resistance elements, and means for rotating said shaft to adjust the position of said contact maker, said resistance elements being under tension so that they will remain in engagement with said contact maker during its adjustment.

17. Ina rheostat, a generally circular block, a pair of resistance elements, notches adjacent the circumference of said block in which the ends of said elements are secured IOU respectively, a pair of terminal members, each having a base port-ion secured within said block, lugs on said terminal members, said resistance elements being passed about the circumference of said block and secured to said lugs respectively, a shaft extending concentrically through said block. a contact maker carried by said shaft and arranged between said resistance elements and the cir- V cumference of said block, and means for rotating said shaft to adjust said contact maker. said resistance elements being maintained by their own tension in engagement with .said contact maker during the movementthereof.

18. In a rheostat, a substantially circular block, terminal members, each having a base portion secured within said block, lugs on said terminal members respectively, notches said block, a pair of resistance elements,

said block having a pair of notches therein in which the ends of said resistance elements respectively are secured, said resistance elements being positioned within said grooves respectively and having the other ends thereof secured to said lugs respectively,

said resistance members being arranged to pass through slots extending inwardly from the circumference of said block to said lugs, a shaft extending concentrically through said block, anarm on said shaft, a contact maker'carried by said arm and positioned between said resistance elements and the circumference of said block, and means for rotating said shaft for adjusting said contact maker about said block, said resistance elements being maintained in engagement with said contact maker by their own tension.

In witness whereof, I hereunto subscribe my name this day of April, 1922. I

JOHN H. MILLER. Witnesses:

DAGMAR PETERSON, EMILE Bonnenors. 

